This invention relates to an information system for motor vehicles.
Vehicle information systems have been developed that provide various types of information to operators of those vehicles. In particular, navigation systems have been developed. One type of navigation system, an autonomous navigation system, uses an on-board map, typically stored on a removable medium such as a compact optical disk (e.g., CD-ROM). The navigation system uses the on-board map to plan a route from a starting point to a destination, which is specified by the operator of the vehicle. Updating an autonomous system""s map, for example to add or correct information, typically involves replacing the removable medium.
In some navigation systems the operator inputs the desired destination (and the current location, if required by the system) by entering a spelling of the destination. Some systems also allow an operator to select from a stored list of xe2x80x9cpoints of interest,xe2x80x9d such as a list of gas stations or restaurants. Once the operator inputs the destination, the system plans a route along the road network to the destination. The route is typically planned to provide a shortest distance or to try to provide the shortest travel time. Once the route is planned, the operator is guided by the system along the route.
Various approaches to route guidance have been used. A particularly simple approach is to provide the operator with a sequence of discrete instructions, for instance, at intersections where the operator must turn from one street onto another. The operator indicates when he or she is ready for the next instruction. For example, the instructions are provided as an audio output, and the operator says xe2x80x9cnextxe2x80x9d when ready for another instruction.
Another approach to route guidance uses a displayed map on which the planned route and the vehicle""s location are dynamically displayed. The operator uses the map to decide when and where to turn in order to follow the planned route.
Some guidance approaches are aided by in-vehicle sensors that are used to estimate the location of the vehicle. For instance, a magnetic compass is used to estimate the direction of travel, and a velocity sensor is used to estimate the distance traveled. In addition, the location of the vehicle can be estimated using the Global Positioning System (GPS). In GPS, multiple satellites emit signals that allow an in-vehicle GPS receiver to estimate its absolute location.
Other types of vehicle information systems have also been developed. In some systems, traffic related information, such as traffic advisories, is broadcast to specially equipped in-vehicle radio receivers.
In general, in one aspect, the invention is a vehicle information system. The vehicle information system features an in-vehicle system and a centralized server system. The in-vehicle system communicates with the server system using a wireless communication link.
In general, in another aspect, the invention is a method for guiding a vehicle through a road network from a starting location to a destination. The method features transmitting a specification of the destination to a server, for example by transmitting a street address or an identifier of a point of interest. The server determines a route to the specified destination and transmits a specification of the route to the vehicle. The method also includes receiving from the server a specification of a planned route through the road network to the destination as well as receiving from the server a map that includes a specification of the road network in the vicinity of the planned route For instance, the map can correspond to one or more regions around particular points on the planned route, correspond to a xe2x80x9ccorridorxe2x80x9d around the planned route, or be a complex shaped region in the vicinity of the route. The planned route can include specifications of a multiple maneuvers to be carried out by the vehicle, and the specification of each maneuver then includes a location of the maneuver. The map can be in the vicinity of the starting location, or in the vicinity of one of the specified maneuvers. The method can also feature tracking the location of the vehicle. The method can also feature displaying the received map in conjunction with a representation of the planned route, and a location of the vehicle.
An advantage of the invention is that the vehicle does not have to have a prestored map to plan a route to a destination. Also, the invention provides a way of displaying a map of the vicinity of the starting point or of intermediate maneuver points of a planned route without requiring that the map be prestored in the vehicle. The displayed map can provide useful information to an operator of a vehicle during difficult maneuvers where turn-by-turn instructions.
In general, in another aspect, the invention is a method for tracking a vehicle. The method features receiving a reference signal from a positioning system, for example receiving signals from GPS satellites, and computing position data related to the location of the vehicle using the received reference signal. For example, the position data can be latitude and longitude estimates, or can be GPS pseudorange measurements. The method also features transmitting the position data to a server and receiving from the server position correction data. For example, the position correction can be a deviation in latitude and longitude, or can be correction terms to be applied to GPS pseudorange measurements. The method also features determining estimated coordinates of the vehicle including combining data computed from the received reference signal and the position correction data.
The method can feature repeatedly computing the position data, and determining the estimated coordinates, including combining the position data and the position correction data. The method can also feature, subsequent to the interval of time, repeatedly computing the position data and determining estimated coordinates of the vehicle using the position data without using the correction data.
In general, in another aspect, the invention is a method for tracking a vehicle. The method features receiving a specification of a first location which includes coordinates, such as latitude and longitude, of the first location. The method includes determining when the vehicle is at or passes near the first location. The method includes computing first position data using a reference signal received from a positioning system at the time at which the vehicle was determined to be at the first location. For instance, the positioning system can be a GPS positioning system, and the computed first position data can include pseudorange measurements derived from GPS satellite signals received when the vehicle was at or near the first location. The method further includes computing position correction data using the first position data and the coordinates of the first location. For instance, computing the position correction data can include computing pseudorange correction data based on the latitude and longitude of the first location and on the pseudorange measurements derived from GPS satellite signals received when the vehicle was at or near the first location. The method further includes computing second position data using a reference signal received from the positioning system at a second time subsequent to the time at which that the vehicle was determined to be at the first location, and then determining coordinates of the vehicle at the second time including combining the correction data and the second position data.
The method can feature including in the specification of the first location a specification of a maneuver to be carried out by the vehicle at the first location. Determining when the vehicle is at the first location then includes detecting when the vehicle performs the specified maneuver, for instance using vehicle sensors such as a compass, accelerometers, or a gyroscope.
In general, in another aspect, the invention is a method for detecting when a vehicle deviates from a planned route. The method features tracking a first estimated position of the vehicle using signals from a positioning system that are received at the vehicle, for example, using a GPS positioning system. The method also features tracking a second estimated position of the vehicle using an estimate of the distance traveled along the planned route. The vehicle is detected to has deviated from the planned route when the first estimated position and the second estimated position differ by at least a tolerance distance.
The method can feature detecting when the vehicle is at a first point on the planned route, such as a maneuver point, and estimating the distance traveled along the path following the first point.
The method can also feature adjusting the tolerance distance, including reducing the tolerance distance when the vehicle is detected to be at the first point on the planned route, and increasing the tolerance distance as the vehicle travels along the path following the first point.
In general, in another aspect, the invention is a method for providing guidance instructions to a vehicle operator following a planned route that includes a sequence of maneuver points. The method includes detecting when the vehicle is at a first maneuver point, and tracking the distance traveled by the vehicle from the first maneuver point along the planned route. When the tracked distance is within a predetermined notification distance of the distance between the first maneuver point and a subsequent maneuver point along the planned route the operator is notified of the subsequent maneuver.
In general, in another aspect, the invention is a method for specifying a location in a vehicle navigation system. The method features providing an in-vehicle map database to an in-vehicle system. The in-vehicle database includes data related to valid location specifications for accessing a server map database at a server system. The method also features accepting a location specification, for instance, for an operator using a user interface in the vehicle. The system validates the location specification using the in-vehicle map database and then transmits the validated location specification to the server system.
The method can also feature providing the server map database to the server system and accessing the server map database using the received validated location specification. In addition the method can also include determining a route to the specified location using the server map database, and transmitting the determined route to the in-vehicle system.
In general, in another aspect, the invention is method for estimating a location of a vehicle. The method includes determining a series of vehicle position estimates using a positioning system, and recording each of the vehicle position estimates in the series. For example, the position estimates are recorded in a non-volatile memory as the vehicle reaches a destination. The method further includes estimating the location of the vehicle including retrieving the most recently recorded in the series of location estimates, for instance after the vehicle is started after a period of being parked at the destination.
The invention has the advantage that a location estimate may be obtained, even if a positioning system, such as a GPS satellite system, is out of range, or prior to the positioning system being initialized.
In general, in another aspect, the invention is a method for vehicle guidance. The method features receiving at the vehicle a planned route to a destination location from a server, and storing the planned route at the vehicle. The method also includes providing instructions to an operator of the vehicle according to the stored planned route, for example, providing instructions at each of a series of maneuvers along the route. The method includes tracking a location of the vehicle and detecting whether the vehicle has deviated from the planned route. If the vehicle is detected to have deviated from the planned route, the method then includes planning a new route to the destination location. Planning the new route does not necessarily require further communication with the server. Planning the new route can include determining the location of the vehicle and accessing a map database stored in the vehicle.
The method can also include establishing a wireless communication channel with the server, transmitting a specification of the destination location over the wireless communication channel, and then terminating the wireless communication channel after receiving the planned route.
Advantages of this method include providing a server based route planning service to a vehicle, without requiring ongoing communication with the server to carry out guidance and route replanning functions.
In general, in another aspect, the invention is a method for collecting traffic information. The method includes tracking the location of a vehicle, including detecting when the vehicle traverses each of a plurality of segments of a road network. For each detected segment, the method includes logging traffic-related data, including logging data related to the vehicle""s speed on the detected segment. The method then includes transmitting the logged data to a server
The method can feature receiving a command from the server to enable logging of the traffic-related data at a vehicle. The method can also feature receiving at a vehicle a request to transmit the logged data to the server.
In general, in another aspect, the invention is a method for collecting traffic information. The method includes tracking the location of a vehicle, including detecting when the vehicle traverses each of a set of segments of a road network. For each detected segment, the method features comparing the vehicle""s speed on the segment to a stored speed for that segment, and if the vehicle""s speed on the segment deviates from the stored speed, transmitting a traffic notification identifying that segment to a server.
In general, in another aspect, the invention is a method for collecting traffic information. The method includes receiving traffic related data from a set of vehicles and updating a traffic database using the received traffic related data. Updating the database includes updating speed information associated with multiple road segments in a road network. The method also features planning a route through the road network from a starting to a destination location using the speed information associated with the road segments.
The method can also feature enabling a subset of an available set of probe vehicles to provide the traffic related data, and can, in addition, feature determining a part of the traffic database to target for updating, for instance, according to a the part of the database corresponding to a geographic area. Enabling the subset of probe vehicles then includes enabling probe vehicles according to the part of the database that is targeted.
In general, in another aspect, the invention is a method for specifying a destination to a vehicle navigation system. The method includes accessing a list of categories of destinations, and accepting a selection from the list of categories, for example, from an operator making the selection on a in-vehicle user interface. The method includes transmitting the selection from the list of categories to a server system, and subsequently receiving a list of destinations from the selected category from the server system. The method then includes accepting a selection from the list of destinations and transmitting the selected destination to the server system.
The method can also feature transmitting data related to the location of the vehicle to the server system. The received list of destinations then includes destinations that are in the vicinity of the vehicle.
In general, in another aspect, the invention is a method for configuring a vehicle navigation system. The method includes providing a server map database to a server. The server map database includes data related to a plurality of road segments in a road network. The method also includes providing a vehicle map database to an in-vehicle system. The vehicle map database includes data related to a subset of the plurality of road segments in the server map database which satisfy a common criterion, for instance related to the road class of the road segments.
In general, in another aspect, the invention is an in-vehicle map database. The database includes a first stored table and a second stored table. The first stored table includes multiple records each including a field containing a reference to a record containing a base name of a street in the second stored table, and a second field which identifies a prefix, a suffix, or a street type. The second stored table includes multiple records, each including a base name of a street stored in a compressed format.
In general, in another aspect, the invention is method for transmitting a route to a vehicle navigation system. The route includes multiple intermediate points joined by road segments. The method includes transmitting a specification of the location of a first of the intermediate points, and transmitting a specification of a difference between the location of a second of the intermediate points and the first of the intermediate points. The specification of the difference can use fewer than an allocated number of bits.
The method can also feature planning an initial route. The initial route includes an initial set of multiple intermediate points coupled by road segments. The planned route is formed from the initial route. For any of the road segments in the initial route for which the difference in locations of the intermediate points bounding that segment is greater than can be specified in the allocated number of bits, the method includes inserting additional intermediate points on that road segment so that the differences between the locations of the adjacent intermediate points can each be specified in the allocated number of bits.
In general, in another aspect, the invention is a vehicle navigation system. The system includes an onboard computer, including storage for a map database, a wireless communication system for passing data between the onboard computer and a remote server, an input/output device for providing a user interface between the onboard computer and an operator of the vehicle, and a vehicle sensor for providing motion-related signals to the onboard computer. The onboard computer is programmed to perform the functions of accepting a planned route from the server over the wireless communication system, maintaining a first location estimate of the vehicle using the motion-related signals from the vehicle sensor, and, using the planned route and the first location estimate, providing guidance instructions to the operator through the input/output device.
In general, in another aspect, the invention is a method for updating an in-vehicle navigation system. The method includes receiving a version number associated with information stored in the in-vehicle system. If the information stored in the in-vehicle system has a version number prior to the version of information a server, the method includes transmitting update information from the server to the in-vehicle system. The information stored in the in-vehicle system can include map data or computer instructions.
The method can feature prioritizing the update information, for instance, according to the geographic area represented by the update information and transmitting the update information in order of the priority.
In general, in another aspect, the invention is a vehicle information server system. The system includes a vehicle communication interface for providing wireless data communication between multiple vehicles and a set of information system. The set of information systems includes a navigation system for accepting route planning request from the vehicles and providing planned routes through the communication interface, and a communication system coupled to an external information system for delivering information from the external information system to the vehicles.
In general, in another aspect, the invention is a method for providing traffic related information to a user. The method features accepting from the user a specification of a path made up of one or more road segments in a road network and receiving traffic data related to road segments in the road network. If the received traffic data indicates an exceptional traffic condition on the specified path, the user is notified of the traffic condition.
Other features and advantages of the invention will be apparent from the following description, and from the claims.